Magnetic devices with overcoats

ABSTRACT

A magnetic device including a magnetic writer; and an overcoat positioned over at least the magnetic writer, the overcoat including oxides of yttrium, oxides of scandium, oxides of lanthanoids, oxides of actionoids, oxides of zinc, or combinations thereof.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No.61/901,615 entitled, DEVICES INCLUDING NEAR FIELD TRANSDUCERS ANDASSOCIATED OVERCOATS, filed on Nov. 8, 2013, the disclosure of which isincorporated herein by reference thereto.

BACKGROUND

The heat assisted magnetic recording (HAMR) process can involve anenvironment that can be extremely corrosive because of the hightemperature (e.g., up to about 450° C.), high humidity, and oxidativeenvironments. Because of the harsh environment and the desire to protectsome of the more delicate structures, for example the near fieldtransducer (NFT) and the write pole for example; there remains a needfor different types of overcoats.

SUMMARY

A magnetic device including a magnetic writer; and an overcoatpositioned over at least the magnetic writer, the overcoat includingoxides of yttrium, oxides of scandium, oxides of lanthanoids, oxides ofactionoids, oxides of zinc, or combinations thereof.

Also disclosed are magnetic devices that include a near field transducer(NFT); and an overcoat positioned over at least a portion of the NFT,the overcoat including an inner layer in contact with the NFT, the innerlayer including oxides of yttrium, oxides of scandium, oxides oflanthanoids, oxides of actionoids, oxides of zinc, or combinationsthereof; and an outer layer in contact with the inner layer, the outerlayer comprising aluminum oxide (Al₂O₃), silicon oxide (SiO₂), tantalumoxide (Ta₂O₅), hafnium oxide (HfO₂), or combinations thereof.

Also disclosed are magnetic devices that include a near field transducer(NFT); and an overcoat positioned over at least a portion of the NFT,the overcoat including an inner layer in contact with the NFT, the innerlayer including oxides of yttrium, oxides of scandium, oxides oflanthanoids, oxides of actionoids, oxides of zinc, or combinationsthereof; and an outer layer in contact with the inner layer, the outerlayer including aluminum oxide (Al₂O₃), silicon oxide (SiO₂), tantalumoxide (Ta₂O₅), hafnium oxide (HfO₂), or combinations thereof.

Also disclosed are magnetic devices that include a magnetic writer, themagnetic writer having a near field transducer (NFT); a magnetic reader;and an overcoat positioned over at least the magnetic writer and themagnetic reader, the overcoat including an inner layer in contact withthe NFT, the inner layer including yttrium, oxide, scandium, oxide, orcombinations thereof; and an outer layer in contact with the innerlayer, the outer layer including aluminum oxide (Al₂O₃), silicon oxide(SiO₂), tantalum oxide (Ta₂O₅), hafnium oxide (HfO₂), or combinationsthereof.

The above summary of the present disclosure is not intended to describeeach disclosed embodiment or every implementation of the presentdisclosure. The description that follows more particularly exemplifiesillustrative embodiments. In several places throughout the application,guidance is provided through lists of examples, which examples can beused in various combinations. In each instance, the recited list servesonly as a representative group and should not be interpreted as anexclusive list.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a pictorial representation of a data storage device in theform of a disc drive that can include a recording head constructed inaccordance with an aspect of this disclosure.

FIG. 2 is a side elevation view of a recording head constructed inaccordance with an aspect of the invention.

FIGS. 3A, 3B, and 3C are schematic depictions of cross sections ofportions of a device (FIGS. 3A and 3B) and a view from the air bearingsurface (ABS) of a device (FIG. 3C).

The figures are not necessarily to scale. Like numbers used in thefigures refer to like components. However, it will be understood thatthe use of a number to refer to a component in a given figure is notintended to limit the component in another figure labeled with the samenumber.

DETAILED DESCRIPTION

Heat assisted magnetic recording (referred to as HAMR) utilizesradiation, for example from a laser, to heat media to a temperatureabove its curie temperature, enabling magnetic recording. In order todeliver the radiation, e.g., a laser beam, to a small area (on the orderof 20 to 50 nm for example) of the medium, a near field transducer (NFT)is utilized. During a magnetic recording operation, the NFT absorbsenergy from a laser and focuses it to a very small area; this can causethe temperature of the NFT to increase. The temperature of the NFT canbe elevated up to about 400° C. or more.

Because of the elevated temperature and harsh environment, layers overthe magnetic head, referred to herein as overcoats can be important. Insome embodiments, overcoats can provide

Disclosed overcoats can advantageously provide devices that may be morerobust in high temperature environments, such as HAMR. Disclosedovercoats include at least oxides of yttrium, oxides of scandium, oxidesof lanthanoids, oxides of actionoids, oxides of zinc, or combinationsthereof.

Disclosed herein are NFTs and devices that include such NFTs. FIG. 1 isa pictorial representation of a data storage device in the form of adisc drive 10 that can utilize disclosed NFTs. The disc drive 10includes a housing 12 (with the upper portion removed and the lowerportion visible in this view) sized and configured to contain thevarious components of the disc drive. The disc drive 10 includes aspindle motor 14 for rotating at least one magnetic storage media 16within the housing. At least one arm 18 is contained within the housing12, with each arm 18 having a first end 20 with a recording head orslider 22, and a second end 24 pivotally mounted on a shaft by a bearing26. An actuator motor 28 is located at the arm's second end 24 forpivoting the arm 18 to position the recording head 22 over a desiredsector or track 27 of the disc 16. The actuator motor 28 is regulated bya controller, which is not shown in this view and is well-known in theart. The storage media may include, for example, continuous media or bitpatterned media.

For heat assisted magnetic recording (HAMR), electromagnetic radiation,for example, visible, infrared or ultraviolet light is directed onto asurface of the data storage media to raise the temperature of alocalized area of the media to facilitate switching of the magnetizationof the area. Recent designs of HAMR recording heads include a thin filmwaveguide on a slider to guide light toward the storage media and a nearfield transducer to focus the light to a spot size smaller than thediffraction limit. While FIG. 1 shows a disc drive, disclosed NFTs canbe utilized in other devices that include a near field transducer.

FIG. 2 is a side elevation view of a recording head that may include adisclosed NFT; the recording head is positioned near a storage media.The recording head 30 includes a substrate 32, a base coat 34 on thesubstrate, a bottom pole 36 on the base coat, and a top pole 38 that ismagnetically coupled to the bottom pole through a yoke or pedestal 40. Awaveguide 42 is positioned between the top and bottom poles. Thewaveguide includes a core layer 44 and cladding layers 46 and 48 onopposite sides of the core layer. The top pole is a two-piece pole thatincludes a first portion, or pole body 52, having a first end 54 that isspaced from the air bearing surface 56, and a second portion, or slopedpole piece 58, extending from the first portion and tilted in adirection toward the NFT. The second portion is structured to include anend adjacent to the air bearing surface 56 of the recording head, withthe end being closer to the waveguide than the first portion of the toppole. A planar coil 60 also extends between the top and bottom poles andaround the pedestal. In this example, the top pole serves as a writepole and the bottom pole serves as a return pole.

An insulating material 62 separates the coil turns. In one example, thesubstrate can be AlTiC, the core layer can be Ta₂O₅, and the claddinglayers (and other insulating layers) can be Al₂O₃. A top layer ofinsulating material 63 can be formed on the top pole. A heat sink 64 ispositioned adjacent to the sloped pole piece 58. The heat sink can becomprised of a non-magnetic material, such as for example Au.

As illustrated in FIG. 2, the recording head 30 includes a structure forheating the magnetic storage media 16 proximate to where the write pole58 applies the magnetic write field H to the storage media 16. In thisexample, the media 16 includes a substrate 68, a heat sink layer 70, amagnetic recording layer 72, and a protective layer 74. However, othertypes of media, such as bit patterned media can be used. A magneticfield H produced by current in the coil 60 is used to control thedirection of magnetization of bits 76 in the recording layer of themedia.

The storage media 16 is positioned adjacent to or under the recordinghead 30. The waveguide 42 conducts light from a source 78 ofelectromagnetic radiation, which may be, for example, ultraviolet,infrared, or visible light. The source may be, for example, a laserdiode, or other suitable laser light source for directing a light beam80 toward the waveguide 42. Specific exemplary types of light sources 78can include, for example laser diodes, light emitting diodes (LEDs),edge emitting laser diodes (EELs), vertical cavity surface emittinglasers (VCSELs), and surface emitting diodes. In some embodiments, thelight source can produce energy having a wavelength of 830 nm, forexample. Various techniques that are known for coupling the light beam80 into the waveguide 42 may be used. Once the light beam 80 is coupledinto the waveguide 42, the light propagates through the waveguide 42toward a truncated end of the waveguide 42 that is formed adjacent theair bearing surface (ABS) of the recording head 30. Light is focused onthe NFT and the energy is transferred from the light to the NFT andsubsequently to the media and heats a portion of the media, as the mediamoves relative to the recording head as shown by arrow 82. A near-fieldtransducer (NFT) 84 is positioned in or adjacent to the waveguide and ator near the air bearing surface. The design may incorporate a heat sinkmade of a thermally conductive material integral to, or in directcontact with, the NFT 84, and chosen such that it does not preventcoupling of electromagnetic energy into and out of the NFT 84. The heatsink may be composed of a single structure or multiple connectedstructures, positioned such that they can transfer heat to othermetallic features in the head and/or to the gas flow external to therecording head.

Although the example of FIG. 2 shows a perpendicular magnetic recordinghead and a perpendicular magnetic storage media, it will be appreciatedthat the disclosure may also be used in conjunction with other types ofrecording heads and/or storage media as well. It should also be notedthat disclosed devices can also be utilized with magnetic recordingdevices other than HAMR devices.

FIG. 3A depicts a device 300 that includes a NFT 305. The NFT 305 caninclude features and characteristics such as those discussed above. Thedevice 300 also includes an overcoat 303. The overcoat 303 depicted inFIG. 3A includes an inner layer 307 and an outer layer 309. The innerlayer 307 may function to provide increased adhesion to the NFT 305. Theouter layer 309 may function to diminish or prevent the amount of gasthat can reach the NFT 305.

The inner layer 307 may include one or more than one material, one ormore than one sublayer, or combinations thereof. The inner layer 307 mayinclude oxides of yttrium, oxides of scandium, oxides of lanthanoids (orlanthanides), oxides of actionoids (or actinides), oxides of zinc, orcombinations thereof. More specifically, the inner layer 307 may includeyttrium oxide (Y₂O₃), scandium oxide (Sc₂O₃), oxides of lanthanoids:lanthanum oxide (La₂O₃), cerium oxide (Ce₂O₃, or CeO₂), praseodymiumoxide (Pr₂O₃), neodymium oxide (Nd₂O₃), promethium oxide (Pm₂O₃),samarium oxide (Sm₂O₃), europium oxide (Eu₂O₃), gadolinium oxide(Gd₂O₃), terbium oxide (Tb₄O₇, Tb₂O₃, TbO₂, or Tb₆O₁₁), dysprosium oxide(Dy₂O₃), holmium oxide (Ho₂O₃), erbium oxide (Er₂O₃), thulium oxide(Tm₂O₃), ytterbium oxide (Yb₂O₃), and lutetium oxide (Lu₂O₃), oxides ofactinoids: actinium oxide (Ac₂O₃), thorium oxide (Th₂O₇ or THO₂),protactinium oxide (Pa₂O₅, PaO₂, or PaO), uranium oxide (U₃O₈, UO₂, UO₃,U₂O₅, or UO₄.2H₂O), neptunium oxide (NpO₂, Np₂O₅, or Np₅O₈), plutoniumoxide (PuO₂ or PuO₄), americium oxide (AmO, Am₂O₃, or AmO₂), curiumoxide (Cm₂O₃, CmO₂, or CmO₄), berkelium oxide (Bk₂O₃, or BkO₂),californium oxide (Cf₂O₃ or CfO₂), einsteinium oxide (Es₂O₃), fermiumoxide (Fm₂O₃, or FmO), mendelevium oxide (Md₂O₃ or MdO), nobelium oxide(No₂O₃ or NoO), and lawrencium oxide (Lr₂O₃), zinc oxide (ZnO), orcombinations thereof. In some embodiments, the inner layer 307 includesyttrium oxide or scandium oxide. In some embodiments, the inner layer307 includes yttrium oxide.

The outer layer 309 may include one or more than one material, one ormore than one sublayer, or combinations thereof. The outer layer 309 mayinclude any material that has relatively low gas permeability. In someembodiments, the outer layer 309 may include aluminum oxide (Al₂O₃),silicon oxide (SiO₂), tantalum oxide (Ta₂O₅), hafnium oxide (HfO₂), orcombinations thereof. In some embodiments, the outer layer 309 is madeup of more than one material. In some embodiments, the outer layer 309is made up of more than one layer. In some embodiments, the outer layer309 is made up of more than one layer of at least two differentmaterials. In some embodiments, the outer layer 309 includes a firstlayer in contact with the inner layer 307 and a second layer in contactwith the first layer. In some embodiments, the second layer includesSiO₂, Ta₂O₅, HfO₂, or combinations thereof as they have a relativelyhigh resistance to hydrothermal corrosion. In some embodiments, thefirst layer includes Al₂O₃. In some embodiments, the outer layer 309 hasa first layer that includes Al₂O₃ and a second layer that includes SiO₂,Ta₂O₅, HfO₂, or combinations thereof. In some embodiments, the outerlayer 309 has a first layer that includes Al₂O₃ and a second layer thatincludes SiO₂.

In some embodiments, the overcoat 303 can have a thickness of notgreater than 100. In some embodiments, the overcoat 303 can have athickness of not greater 70 Å. In some embodiments, the overcoat 303 canhave a thickness of not less than 10 Å. In some embodiments, theovercoat 303 can have a thickness of not less than 20 Å. In someembodiments, the inner layer 307 can have a thickness of not greaterthan 50 Å. In some embodiments, the inner layer 307 can have a thicknessof not greater than 30 Å. In some embodiments, the inner layer 307 canhave a thickness of not less than 10 Å. In some embodiments, the innerlayer 307 can have a thickness of not less than 20 Å. In someembodiments, the outer layer 309 can have a thickness of not greaterthan 90 Å. In some embodiments, the outer layer 309 can have a thicknessof not greater than 60 Å. In some embodiments, the outer layer 309 canhave a thickness of not less than 10 Å. In some embodiments, the outerlayer 309 can have a thickness of not less than 20 Å.

FIG. 3B depicts a similar device 320 that includes a NFT 325 and anovercoat 304. The overcoat depicted in FIG. 3B includes an inner layer307, an outer layer 309 and an optional exterior layer 331. The innerlayer 307 and the outer layer 309 may have properties andcharacteristics such as those discussed above with respect to FIG. 3A.The exterior layer 331 can include materials such as, for example carboncontaining materials (such as diamond like carbon (DLC)), magneticmaterials, molecular materials, and oxides such as tantalum oxide.Specific details regarding materials for the optional exterior layer canbe found, for example in U.S. patent application Ser. No. 14/313,611filed on Jun. 24, 2014, entitled “DEVICES INCLUDING A GAS BARRIERLAYER”, the entire disclosure of which is incorporated herein byreference thereto.

FIG. 3C depicts a view looking down at the air bearing surface (ABS) ofa device 350. The device 350 can include a magnetic structure 355 and amagnetic writer 351. The magnetic writer 351 can have details such asthose discussed above. The magnetic structure 355 can include a magneticreader, a return pole, or some combination thereof. In some embodiments,the magnetic writer 351 can also include a NFT, such as those discussedabove. The device also includes an overcoat. The overcoat is positionedover at least the NFT included in the magnetic writer. In someembodiments, the overcoat can be positioned over more than just the NFTof the magnetic writer (i.e., the entire magnetic writer, some portionof the magnetic reader, or both). The overcoat can be a continuouslayer, or a non-continuous layer that is positioned over at least aportion of the NFT on the air bearing surface of the device. In someembodiments, disclosed overcoats are disposed on the entire magneticwriter structure (including the NFT), and at least some portion of themagnetic reader. In some embodiments, overcoats can also include regionsthat are continuous as well as non-continuous regions; such overcoatsare described herein as non-continuous.

Layers disclosed herein, including inner layers, outer layers andoptional exterior layers can be formed using known methods, including,for example physical vapor deposition (PVD), chemical vapor deposition(CVD), and atomic layer deposition (ALD). In some embodiments, innerlayers, outer layers, optional exterior layers, or any combinationthereof can be formed using ALD, for example. In some embodiments, atleast some layers included in disclosed devices can have low opticalabsorption (e.g., k, 0.001). In some embodiments, at least the innerlayer has a low optical absorption. In some embodiments, such lowoptical absorptive materials can be formed using physical vapordeposition (PVD), chemical vapor deposition (CVD), and/or atomic layerdeposition (ALD). In some embodiments, outer layers formed using ALD aredesirably dense and non-permeable.

Disclosed devices can offer advantageous properties, especially in thehigh temperature, high humidity, and highly oxidative environments ofHAMR. Such devices may offer minimal optical absorption, low gas (e.g.,H₂O, O₂, or both) permeability, and strong adhesion between the overcoatand the NFT. Such properties may offer extended lifetimes for HAMRdrives during practical usage by diminishing the corrosive effects ofthe HAMR environment and decreasing the likelihood of NFT recession.

All scientific and technical terms used herein have meanings commonlyused in the art unless otherwise specified. The definitions providedherein are to facilitate understanding of certain terms used frequentlyherein and are not meant to limit the scope of the present disclosure.

As used in this specification and the appended claims, “top” and“bottom” (or other terms like “upper” and “lower”) are utilized strictlyfor relative descriptions and do not imply any overall orientation ofthe article in which the described element is located.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” encompass embodiments having pluralreferents, unless the content clearly dictates otherwise.

As used in this specification and the appended claims, the term “or” isgenerally employed in its sense including “and/or” unless the contentclearly dictates otherwise. The term “and/or” means one or all of thelisted elements or a combination of any two or more of the listedelements.

As used herein, “have”, “having”, “include”, “including”, “comprise”,“comprising” or the like are used in their open ended sense, andgenerally mean “including, but not limited to”. It will be understoodthat “consisting essentially of”, “consisting of”, and the like aresubsumed in “comprising” and the like. For example, a conductive tracethat “comprises” silver may be a conductive trace that “consists of”silver or that “consists essentially of” silver.

As used herein, “consisting essentially of,” as it relates to acomposition, apparatus, system, method or the like, means that thecomponents of the composition, apparatus, system, method or the like arelimited to the enumerated components and any other components that donot materially affect the basic and novel characteristic(s) of thecomposition, apparatus, system, method or the like.

The words “preferred” and “preferably” refer to embodiments that mayafford certain benefits, under certain circumstances. However, otherembodiments may also be preferred, under the same or othercircumstances. Furthermore, the recitation of one or more preferredembodiments does not imply that other embodiments are not useful, and isnot intended to exclude other embodiments from the scope of thedisclosure, including the claims.

Also herein, the recitations of numerical ranges by endpoints includeall numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2,2.75, 3, 3.80, 4, 5, etc. or 10 or less includes 10, 9.4, 7.6, 5, 4.3,2.9, 1.62, 0.3, etc.). Where a range of values is “up to” a particularvalue, that value is included within the range.

Use of “first,” “second,” etc. in the description above and the claimsthat follow is not intended to necessarily indicate that the enumeratednumber of objects are present. For example, a “second” substrate ismerely intended to differentiate from another infusion device (such as a“first” substrate). Use of “first,” “second,” etc. in the descriptionabove and the claims that follow is also not necessarily intended toindicate that one comes earlier in time than the other.

Thus, embodiments of magnetic devices including overcoats are disclosed.The implementations described above and other implementations are withinthe scope of the following claims. One skilled in the art willappreciate that the present disclosure can be practiced with embodimentsother than those disclosed. The disclosed embodiments are presented forpurposes of illustration and not limitation.

What is claimed is:
 1. A magnetic device having an air bearing surface,the magnetic device comprising: a near field transducer (NFT); and anovercoat positioned over at least a portion of the NFT at the airbearing surface of the device, the overcoat comprising an inner layer incontact with the NFT and an outer layer in contact with the inner layer,wherein the inner layer comprises oxides of yttrium, oxides of scandium,oxides of lanthanoids, oxides of actionoids, oxides of zinc, orcombinations thereof.
 2. The magnetic device according to claim 1,wherein the inner layer comprises yttrium oxide (Y₂O₃), scandium oxide(Sc₂O₃), oxides of lanthanoids: lanthanum oxide (La₂O₃), cerium oxide(Ce₂O₃, or CeO₂), praseodymium oxide (Pr₂O₃), neodymium oxide (Nd₂O₃),promethium oxide (Pm₂O₃), samarium oxide (Sm₂O₃), europium oxide(Eu₂O₃), gadolinium oxide (Gd₂O₃), terbium oxide (Tb₄O₇, Tb₂O₃, TbO₂, orTb₆O₁₁), dysprosium oxide (Dy₂O₃), holmium oxide (Ho₂O₃), erbium oxide(Er₂O₃), thulium oxide (Tm₂O₃), ytterbium oxide (Yb₂O₃), and lutetiumoxide (Lu₂O₃), oxides of actinoids: actinium oxide (Ac₂O₃), thoriumoxide (Th₂O₇ or THO₂), protactinium oxide (Pa₂O₅, PaO₂, or PaO), uraniumoxide (U₃O₈, UO₂, UO₃, U₂O₅, or UO₄.2H₂O), neptunium oxide (NpO₂, Np₂O₅,or Np₅O₈), plutonium oxide (PuO₂ or PuO₄), americium oxide (AmO, Am₂O₃,or AmO₂), curium oxide (Cm₂O₃, CmO₂, or CmO₄), berkelium oxide (Bk₂O₃,or BkO₂), californium oxide (Cf₂O₃ or CfO₂), einsteinium oxide (Es₂O₃),fermium oxide (Fm₂O₃, or FmO), mendelevium oxide (Md₂O₃ or MdO),nobelium oxide (No₂O₃ or NoO), and lawrencium oxide (Lr₂O₃), zinc oxide(ZnO), or combinations thereof.
 3. The magnetic device according toclaim 1, wherein the inner layer comprises yttrium oxide (Y₂O₃),scandium oxide (Sc₂O₃), or combinations thereof.
 4. The magnetic deviceaccording to claim 1, wherein the inner layer comprises yttrium oxide(Y₂O₃).
 5. The magnetic device according to claim 1, wherein the outerlayer comprises aluminum oxide (Al₂O₃), silicon oxide (SiO₂), tantalumoxide (Ta₂O₅), hafnium oxide (HfO₂), or combinations thereof.
 6. Themagnetic device according to claim 1, wherein the outer layer comprisesaluminum oxide (Al₂O₃), and silicon oxide (SiO₂).
 7. The magnetic deviceaccording to claim 1, wherein the outer layer comprises a first layer incontact with the inner layer the first layer comprising aluminum oxide(Al₂O₃), and a second layer in contact with the first layer, the secondlayer comprising silicon oxide (SiO₂).
 8. The magnetic device accordingto claim 1, wherein the overcoat has a thickness from about 5 Å to about100 Å.
 9. The magnetic device according to claim 1 further comprising anexterior layer in contact with the outer layer of the overcoat.
 10. Themagnetic device according to claim 9, the exterior layer comprisingdiamond like carbon (DLC).
 11. A magnetic device having an air bearingsurface, the magnetic device comprising: a near field transducer (NFT);and an overcoat positioned over at least a portion of the NFT at the airbearing surface of the magnetic device, the overcoat comprising: aninner layer in contact with the NFT, the inner layer comprising oxidesof yttrium, oxides of scandium, oxides of lanthanoids, oxides ofactionoids, oxides of zinc, or combinations thereof; and an outer layerin contact with the inner layer, the outer layer comprising aluminumoxide (Al₂O₃), silicon oxide (SiO₂), tantalum oxide (Ta₂O₅), hafniumoxide (HfO₂), or combinations thereof.
 12. The magnetic device accordingto claim 11, wherein the inner layer comprises yttrium oxide (Y₂O₃),scandium oxide (Sc₂O₃), oxides of lanthanoids: lanthanum oxide (La₂O₃),cerium oxide (Ce₂O₃, or CeO₂), praseodymium oxide (Pr₂O₃), neodymiumoxide (Nd₂O₃), promethium oxide (Pm₂O₃), samarium oxide (Sm₂O₃),europium oxide (Eu₂O₃), gadolinium oxide (Gd₂O₃), terbium oxide (Tb₄O₇,Tb₂O₃, TbO₂, or Tb₆O₁₁), dysprosium oxide (Dy₂O₃), holmium oxide(Ho₂O₃), erbium oxide (Er₂O₃), thulium oxide (Tm₂O₃), ytterbium oxide(Yb₂O₃), and lutetium oxide (Lu₂O₃), oxides of actinoids: actinium oxide(Ac₂O₃), thorium oxide (Th₂O₇ or THO₂), protactinium oxide (Pa₂O₅, PaO₂,or PaO), uranium oxide (U₃O₈, UO₂, UO₃, U₂O₅, or UO₄.2H₂O), neptuniumoxide (NpO₂, Np₂O₅, or Np₅O₈), plutonium oxide (PuO₂ or PuO₄), americiumoxide (AmO, Am₂O₃, or AmO₂), curium oxide (Cm₂O₃, CmO₂, or CmO₄),berkelium oxide (Bk₂O₃, or BkO₂), californium oxide (Cf₂O₃ or CfO₂),einsteinium oxide (Es₂O₃), fermium oxide (Fm₂O₃, or FmO), mendeleviumoxide (Md₂O₃ or MdO), nobelium oxide (No₂O₃ or NoO), and lawrenciumoxide (Lr₂O₃), zinc oxide (ZnO), or combinations thereof.
 13. Themagnetic device according to claim 11, wherein the inner layer comprisesyttrium oxide (Y₂O₃), scandium oxide (Sc₂O₃), or combinations thereof.14. The magnetic device according to claim 11, wherein the inner layercomprises yttrium oxide (Y₂O₃).
 15. The magnetic device according toclaim 11, wherein the outer layer comprises aluminum oxide (Al₂O₃), andsilicon oxide (SiO₂).
 16. The magnetic device according to claim 11,wherein the outer layer comprises a first layer in contact with theinner layer the first layer comprising aluminum oxide (Al₂O₃), and asecond layer in contact with the first layer, the second layercomprising silicon oxide (SiO₂).
 17. The magnetic device according toclaim 11, wherein the overcoat has a thickness from about 5 Å to about100 Å.
 18. The magnetic device according to claim 11 further comprisingan exterior layer in contact with the outer layer of the overcoat, theexterior layer comprising diamond like carbon (DLC).
 19. A magneticdevice having an air bearing surface, the magnetic device comprising: amagnetic writer, the magnetic writer comprising a near field transducer(NFT); a magnetic reader; and an overcoat positioned over at least themagnetic writer and the magnetic reader at the air bearing surface ofthe magnetic device, the overcoat comprising: an inner layer in contactwith the NFT, the inner layer comprising yttrium, oxide, scandium,oxide, or combinations thereof; and an outer layer in contact with theinner layer, the outer layer comprising aluminum oxide (Al₂O₃), siliconoxide (SiO₂), tantalum oxide (Ta₂O₅), hafnium oxide (HfO₂), orcombinations thereof.
 20. The device according to claim 19, wherein theouter layer comprises a first layer in contact with the inner layer thefirst layer comprising aluminum oxide (Al₂O₃), and a second layer incontact with the first layer, the second layer comprising silicon oxide(SiO₂).